Peer Connection Management

class RTCPeerConnection:
    def __init__(self, configuration=None):
        """
        Create a new RTCPeerConnection.
        
        Parameters:
        - configuration (RTCConfiguration, optional): Connection configuration
        """

    # Properties
    @property
    def connectionState(self) -> str:
        """Current connection state: "new", "connecting", "connected", "disconnected", "failed", "closed" """
    
    @property
    def iceConnectionState(self) -> str:
        """ICE connection state: "new", "checking", "connected", "completed", "failed", "disconnected", "closed" """
    
    @property
    def iceGatheringState(self) -> str:
        """ICE gathering state: "new", "gathering", "complete" """
    
    @property
    def localDescription(self) -> RTCSessionDescription:
        """Local session description"""
    
    @property
    def remoteDescription(self) -> RTCSessionDescription:
        """Remote session description"""
    
    @property
    def signalingState(self) -> str:
        """Signaling state: "stable", "have-local-offer", "have-remote-offer", "have-local-pranswer", "have-remote-pranswer", "closed" """
    
    @property
    def sctp(self) -> Optional[RTCSctpTransport]:
        """SCTP transport for data channels, or None if not available"""

    # Session Description Methods
    async def createOffer(self) -> RTCSessionDescription:
        """
        Create an offer session description.
        
        Returns:
        RTCSessionDescription: SDP offer
        """

    async def createAnswer(self) -> RTCSessionDescription:
        """
        Create an answer session description.
        
        Returns:
        RTCSessionDescription: SDP answer
        """

    async def setLocalDescription(self, description: RTCSessionDescription) -> None:
        """
        Set the local session description.
        
        Parameters:
        - description (RTCSessionDescription): Local SDP offer or answer
        """

    async def setRemoteDescription(self, description: RTCSessionDescription) -> None:
        """
        Set the remote session description.
        
        Parameters:
        - description (RTCSessionDescription): Remote SDP offer or answer
        """

    # ICE Candidate Management
    async def addIceCandidate(self, candidate: RTCIceCandidate) -> None:
        """
        Add a remote ICE candidate.
        
        Parameters:
        - candidate (RTCIceCandidate): Remote ICE candidate
        """

    # Media Track Management
    def addTrack(self, track: MediaStreamTrack, *streams) -> RTCRtpSender:
        """
        Add a media track to the connection.
        
        Parameters:
        - track (MediaStreamTrack): Audio or video track to add
        - streams: Associated media streams (unused in current implementation)
        
        Returns:
        RTCRtpSender: RTP sender for the track
        """

    def addTransceiver(self, trackOrKind, direction="sendrecv") -> RTCRtpTransceiver:
        """
        Add an RTP transceiver.
        
        Parameters:
        - trackOrKind: MediaStreamTrack or media kind string ("audio", "video")
        - direction (str): Transceiver direction ("sendrecv", "sendonly", "recvonly", "inactive")
        
        Returns:
        RTCRtpTransceiver: Created transceiver
        """

    # Data Channel Management
    def createDataChannel(self, label: str, **options) -> RTCDataChannel:
        """
        Create a data channel.
        
        Parameters:
        - label (str): Channel label/name
        - maxPacketLifeTime (int, optional): Maximum packet lifetime in milliseconds
        - maxRetransmits (int, optional): Maximum retransmission attempts
        - ordered (bool, optional): Whether to guarantee ordered delivery (default: True)
        - protocol (str, optional): Subprotocol name
        - negotiated (bool, optional): Whether channel is pre-negotiated (default: False)
        - id (int, optional): Numeric channel identifier (0-65534)
        
        Returns:
        RTCDataChannel: Created data channel
        """

    # Information Methods
    def getReceivers(self) -> list:
        """
        Get list of RTP receivers.
        
        Returns:
        list: List of RTCRtpReceiver objects
        """

    def getSenders(self) -> list:
        """
        Get list of RTP senders.
        
        Returns:
        list: List of RTCRtpSender objects
        """

    def getTransceivers(self) -> list:
        """
        Get list of RTP transceivers.
        
        Returns:
        list: List of RTCRtpTransceiver objects
        """

    async def getStats(self) -> RTCStatsReport:
        """
        Get connection statistics.
        
        Returns:
        RTCStatsReport: Statistics for all tracks and transports
        """

    # Connection Management
    async def close(self) -> None:
        """Close the peer connection and release resources."""

class RTCSessionDescription:
    def __init__(self, sdp: str, type: str):
        """
        Create a session description.
        
        Parameters:
        - sdp (str): Session Description Protocol string
        - type (str): Description type ("offer", "answer", "pranswer", "rollback")
        """
    
    @property
    def sdp(self) -> str:
        """SDP string content"""
    
    @property
    def type(self) -> str:
        """Description type"""

import aiortc
import asyncio

async def setup_peer_connection():
    # Create configuration with STUN server
    config = aiortc.RTCConfiguration(
        iceServers=[aiortc.RTCIceServer("stun:stun.l.google.com:19302")]
    )
    
    # Create peer connection
    pc = aiortc.RTCPeerConnection(configuration=config)
    
    # Add event listeners
    @pc.on("connectionstatechange")
    def on_connectionstatechange():
        print(f"Connection state: {pc.connectionState}")
    
    @pc.on("icecandidate")
    def on_icecandidate(candidate):
        # Send candidate to remote peer
        print(f"New ICE candidate: {candidate}")
    
    return pc

pc = asyncio.run(setup_peer_connection())

async def create_offer_answer():
    pc1 = aiortc.RTCPeerConnection()
    pc2 = aiortc.RTCPeerConnection()
    
    # PC1 creates offer
    offer = await pc1.createOffer()
    await pc1.setLocalDescription(offer)
    
    # PC2 processes offer and creates answer
    await pc2.setRemoteDescription(offer)
    answer = await pc2.createAnswer()
    await pc2.setLocalDescription(answer)
    
    # PC1 processes answer
    await pc1.setRemoteDescription(answer)
    
    # Connections are now established (pending ICE)
    print(f"PC1 signaling state: {pc1.signalingState}")
    print(f"PC2 signaling state: {pc2.signalingState}")

async def add_media_and_data():
    pc = aiortc.RTCPeerConnection()
    
    # Add audio and video tracks
    audio_track = aiortc.AudioStreamTrack()
    video_track = aiortc.VideoStreamTrack()
    
    pc.addTrack(audio_track)
    pc.addTrack(video_track)
    
    # Create data channel
    channel = pc.createDataChannel("chat", ordered=True)
    
    @channel.on("open")
    def on_open():
        print("Data channel opened")
        channel.send("Hello WebRTC!")
    
    @channel.on("message")
    def on_message(message):
        print(f"Received: {message}")
    
    # Get connection info
    senders = pc.getSenders()
    receivers = pc.getReceivers()
    transceivers = pc.getTransceivers()
    
    print(f"Senders: {len(senders)}")
    print(f"Receivers: {len(receivers)}")
    print(f"Transceivers: {len(transceivers)}")

from typing import Optional
from aiortc import RTCSctpTransport

# Optional type for nullable values
Optional[T]  # Union of T and None